Enabling option 1M extended acquisition memory Tektronix TDS754A

[Jay_Diddy_B]

Hi,
I am going to share how I enabled option 1M on a Tektronix TDS754A. This can be done without opening the case. I am going to take you through the process that I used step by step.

*** Edit: This has also been tested successfully on a TDS744A ***

Equipment List

Compaq Deskpro 2000 Pentium 133 MHz PC with an ISA bus slot
National Instruments GPIB PC II/IIA card
GPIB cable

Software

Borland C  was used to compile the C program
The NI GPIB software drivers for DOS

Computer Preparation

The GPIB board was installed in the PC with the switches and jumpers set like this:




The board is configured for No DMA, IRQ 7 and base address 0x02E1.

The NI instrument drivers were installed. This puts the following line in Config.sys:



I then ran the NI utility IBCONFIG. I had to adjust the address to match the board address:



Software

I wrote a small program in C that will send the following commands to the scope.

send_scope("PASSWORD PITBULL");
send_scope("WORDCONSTANT:ATPUT 327686,1");

These are the lines in the program that actually enables the option.

I have attached the C code below in a file options_c.txt

I compiled the program with Borland C to make a DOS executable.

You will probably have to modify the program for other GPIB adapters. I made it work with the GPIB hardware that I already had.

Using the Program

Connect the scope to the GPIB board with a cable.

Turn on the scope and wait for the boot to complete.

Access GPIB address menu from Utility -> I/O.

Set the GPIB address to 1: ( I hard coded the address to 1 in my program)




You now need to unprotect the NVRAM. There is a switch located behind two holes in the cover as shown in this diagram:




Run the DOS program

Now set the switch back to the protected position.

Turn the scope off and then back on. You should see 1M added to the options list:




If you go to the horizontal menu you should now be able to set the record length to 500,000 points for a single channel, 250,000 points for two channels and 125,000 points for four channels.



This process worked for me with the two TD754A scopes in my collection. It should be considered as experimental. You are advised to perform a back-up of your NVRAM. My scope had 32 AS7C164 RAM chips on each side of the board. The chips are 8K x 8 so 64 chips is 512K of acquisition memory.

Enjoy !!!

Regards,

Jay_Diddy_B

Acknowledgement: This process was pieced together from information found on this forum, Tek's forum and the Yahoo Group Tekscopes. Without this information this would have not been possible. Many thanks !!

[cncjerry]

Pretty cool. I wonder if it works for a 744a that was upgraded to a 784a?

Also, is 'Pit Bull' a standard password?

[Jay_Diddy_B]

Pretty cool. I wonder if it works for a 744a that was upgraded to a 784a?

Also, is 'Pit Bull' a standard password?

I have a TDS744A I will am reasonably sure that the same technique will work, assuming that the board has the RAM chips installed on both sides. I will have a look at mine later today.

The password 'PITBULL' is found in the Tektronix Field Adjustment Software, so it is reasonable to believe that should always work.

I am deciding if I want to try upgrading a 744A to 784A myself. I have the equipment and software to adjust and calibrate the scope after the modification.

Since the x10 probes are limited to 500 MHz the benefit of changing the scope from 500 MHz to 1 GHz is only useful when using 50 Ohms or active probes. I am not sure how much use this will be to me.

Enabling the extended acquisition memory is going to very useful.

If I do the modification, I will document the risetime and frequency response before and after conversion and adjustment.


Regards,

Jay_Diddy_B

[Jay_Diddy_B]

Hi,
Today I tested the software on a TDS744A.

Acquisition Board Hardware

Here are some pictures of the Acquisition Board in my TDS744A:



It is interesting that this board does not have any of the electrolytic capacitors that leak and cause problems.

This a picture of the attenuator housing, it is identical to the one in my TDS754A:



The label on the board and the RAM chips, the chips are 8K x 8, there 32 pieces on each side:




Enabling option 1M

Here is a screen shot before modification:



And after hooking up the GPIB and running the program:




I then checked the Horzitontal menu:


I was concerned that I could only select 50,000 points:



I then released that the scope was in the HiRes acquisition mode:



If I set the scope to sample mode, I can get the full 500K points on a single channel:



So the technique for enabling option 1M works equally well on a TDS744A.

Regards,

Jay_Diddy_B

[cncjerry]

Thanks for testing on the 744a. I was headed down to my lab Thursday to give it a look using Tek Visa when I slipped in the rain and made a new elbow in my right forearm. Snapped both bones so I have to get that sorted out before trying again. I figured I could just use tek visa or NIVisa and issue the commands, no?

Also, I bought an active probe on ebay and thought I got a good deal. 750Mhz for under $100.

[sorenkir]

Worked with my TDS520B !

Simply by sending (after protection switch activation) :
  PASSWORD PITBULL
  WORDCONSTANT:ATPUT 327686,1
over the GPIB bus with the "NI488-2 Communicator" Utility of my NI GPIB card.

Thanks,
Michel.

[cncjerry]

OK, I started out with a TDS 744a a few months ago and following these and other instructions, I now have a TDS 784A with option 1M.  Thank you, thank you, thank you!

Jerry

[rx8pilot]

I just got a TDS754C - wondering if this is good with the C models.
Would be nice to have for sure.

[Jay_Diddy_B]

I just got a TDS754C - wondering if this is good with the C models.
Would be nice to have for sure.

rx8pilot and the group,

The technique should work for the TDS754C. The memory address was obtained from the Tektronix Field Adjustment software. It is the same address in the TDS754C scope.

Regards,

Jay_Diddy_B

[rx8pilot]

Fantastic, thank you. I will get a bit more time out of this scope if I can get through the process.

[Jay_Diddy_B]

Hi,

Here are the National Instruments DOS drivers for the GPIB PC II/IIa card. I have also attached the manual for the board.


Regards,

Jay_Diddy_B

[tford]

Getting a hold of a NI HPIB card and an old ISA PC is not easy. I can easily buy a Keysight 82357B USB / GPIB Interface device. Would it work with a modern PC to send commands to enable the 1M option on my TDS744?
I don't have much experience in this area. Thanks

[nctnico]

IMHO you should be able to do this with an USB GPIB adapter and National Instruments' free software. You'll have to send the command manually but copy & pasting them isn't difficult.

[Giaime]

Hello all,

I just did the trick with a 744A with the Keysight 82357B. I used the "Agilent Interactive IO" to send the two commands:

 PASSWORD PITBULL
 WORDCONSTANT:ATPUT 327686,1

And magically there's the 1M option shown on startup screen!!! Thanks! 

[Jay_Diddy_B]

Hello all,

I just did the trick with a 744A with the Keysight 82357B. I used the "Agilent Interactive IO" to send the two commands:

 PASSWORD PITBULL
 WORDCONSTANT:ATPUT 327686,1

And magically there's the 1M option shown on startup screen!!! Thanks! 

The next step is to upgrade it to the 784A

Link: https://www.eevblog.com/forum/testgear/conversion-of-500mhz-tds744a-to-1ghz-tds784a/msg568463/#msg568463

Regards,

Jay_Diddy_B

[Levi8than]

This is awesome.  I borrowed an agilent usb2gpib adapter and got the connection working over the open source Linux-GPIB.
Commands worked right out of the box and my tds754c now has 500k records support.  Thanks so much Jay Diddy.

The 500MHz to 1 GHz upgrade sounds tempting.  But I don't the calibration SW (or a 1GHz probe), I'll pass on that for now.

Still, magic.  So thanks.

[tchiwam]

I wanted to add that I tested the TDS694 v6.2e and v6.4e and it worked

I did this with a Prologix GPIB Ethernet

*IDN?
'TEKTRONIX,TDS 694C,0,CF:91.1CT FV:v6.2e\n'
PASSWORD PITBULL
WORDCONSTANT:ATPUT 327686,1    <<<  For the 1M option

I now have a 13 1F 1M 2F